When I stopped using Microsoft Outlook (Mac version) and switched back to native Mac Mail, I had many problems.
Since I also dropped emails that required Exchange mail server (Microsoft back-end email servers), I moved my personal email to Gmail and my business email to FastMail.
But, sorry for burying the lead, I decided the best way for me to avoid wasting so much time in email (both usage and administering it) was to make it harder to use.
I experimented with only using email through web interfaces for a month and that was two years ago.
Using two different tabs - one for FastMail Web and one for Gmail Web, has made it easier to switch context. Their look so different visually, I don’t get confused between business and personal email.
Their Web UI’s have some advantages and quirks, but the friction of not using native email has really helped me with my “email habit”.
Also, MacMail native still has a few show-stopper features missing for me so going native wouldn’t simplify things enough for me.
I do really enjoy not dealing with local email files/message stores, no backup, and no worries about re-installing email when I upgrade or switch between systems (MacBook, MacStudio, iPad)
I do use “native” email on my iPhone, because all alternatives were not appealing and I mainly do a quick cull or reply, but otherwise do very little email on my iPhone itself.
Not for everyone, I know, but seems to work for me.